Television



Aug. 23, 1932. 5 55 ET A 1,873,411

TELEVISION I Original Filed June 26, 1929 2 Sheets-Sheet l F/GJ.

' #5. IVES Arm /w E GPA),

Aug. 23, 1932. H. E. IVES ET AL 4 1 TELEVISION Original Fild June 26. 192s 2 Sheets-She et 2 Hill/xii N awmrom E ATTO/PNEY Patented Aug. 23, 1932 UNITED STATES PATENT. OFFICE HERBERT n rvns, or MONTCLAIR, NEW JERsExAND FRANK GRAY, or NEW YORK,

N. Y., ASSIGNORS TO BELL TELEPHONE LABORATORIES, INCORPORATED, NEW

' YORK, N. Y., A CORPORATION OF NEW YORK TELEVISION d Application filed June 26, 1929, Serial No. 373,769. Renewed- October 6, 1931.-

v This invention relates to television and more particularly to scanning booths for televisionsystems. l i

An object of the invention is to provide an improved arrangement for television scanning of the type in which the person or other subjectjis scanned by means of a traveling beam of light. Y

Another object of the invention is toprovide an improved arrangement ofphotoelectrio cells for receiving light reflected from the subject in the light beam method of scanning. j l

Another object is to effect improvements in booths employed in television systems,and more particularly in such systems for producing an image in natural color.

This invention pertains particularly to the type of television apparatus in which an intense beamof light from an arc lamp'or other source is caused to traverse the person or other subject scanned in parallel adjacent electric cells is provided with a red linesand light reflected from the subject is collected upon large photoelectric cells. These cells haveheretofore been arranged in a general plane in front of the subject and at one side of, or more or less around, an opening which the subject faces and through which the scanning beam is projected. Such an arrangement is disclosed in an applica tion of F rank Gray, Serial No. 227 ,649, filed October 21, 1927. A similar scanning system has been suggested for television in natural colors,- in which case a portion of the photoglass filter, a second portion with a blue filter and ,a third portion, with a green filter. Photoelectric currents set up by the red, blue and green light thusselected are transmitted over separate channels to the receiving station where they control red, blue and green sources of light, respectively, to produce the image in colors. See application of H. E. Ives, Serial No. 218,631,1iled September 10, 1927.

I In accordance with the present invention a cabinet or booth is provided for the person or other object to be scanned and the photoelectric cells are arranged in the cabinet in a manner to give improved results. Ithas been found that theappearanceof depth of an image of three dimensional objects can be {V greatly improved by placing a portionat least of the cells on theside walls or top or bottom of the cabinet rather than having all of the cells on the front inner wall of the cab net toward which the subject faces. In accordance with the preferred arrangement of the invention three groups of large photoele ctriccells-are provided. One group is at the right of thesubject, one attheleft and one above. The ones at-the right'and left maybe arranged in vertical planescoincident With or parallel to thesides of the cabinet, and the one at the top may be in a horizontal plane. The preferred arrangement is to have all of these planes converge somewhat toward the front of the cabinet. Preferably, there is a considerable space on the front wall'of the cabinet, on whichno cells are placed,

which arrangement has the advantage that eyeglasses worn by apersonbeingscaiined does not causetroublesome light reflection. Mirrors may be employed within the cabinet to increase the amount, of light gathered by the 'cellsfrom the subject.

. Also,;in the preferred arrangement' the photoelectric cell material extends backward from the front of'the cabinet to such a olisk tance that portions of it lie at the sides of theobj ect or objects in the field so that alarge. part of the light reflected from the scanned elemental areas which are most remote from the frontof the cabinet will be'collectedby the. light sensitive material. 'If :all ofjthe light sensitive, materialis infront'of a plane parallel to the frontof thecabinet relatively less light from this area reachesthephotoelectric material than from the elemental areas which are nearer thefrontof'the cabinet. That is, when the, head of a-person is being scanned it is necessary'for best results that the photoelectric material lie both to the sides of the persons head and well in 1 This has not been the pracfront thereof. 7 tice heretofore with the result that 'theisioles of the head in the image appear dark and indistinct as though insufficiently illuminated. For the most natural reproduction it is essential alsothat the light sensitive material beso distributedthat a considerable porif the field were of considerable depth "as for. example a tneater stage. r V I y of the invention hereinafter described the forwards or backwards is to be permitted the subject or subjects, it is desirable that the photoelectric material be positioned not only at the; sides 1 orjrear extendsifrom there; forward to the front. of the field.

material would be particularly advantageous In the embodiment systemis designed particularly for scanning a person in, a relatively fixed position so that a' relatively more lateral extent of the photoelectric material is sufiicient. If a field of great depth is scanned it is desirable also to extend the portion of the photoele tric m'aterial which is at the front of the field or above the subjector subjects backward toward the rear ofthefield.

r A .fo'rmof the invention herein chosen for purposes of illustration will now be described, reference being made to the accompanying drawings inwhich: 7 j

. Fig. 1 isja' perspective View partly broken away," of a' cabinet or booth in accordance with the invention;

Fig. 2 is an elevationpartly in section of a photoelectric. cell compartment containing *twojcells;

I Fig.3 is afdiagramof the electrical and optical circuits of a three channel system for television in natural colors. i i Referring to Fig.1,the cabinet or booth 1 comprisesthe front wall 2 on theoutside of which is a 'boXlike projection 3 having an opening 4:

through which the scanning beam isv projected. At each side of the cabinet is a compartment 5 containing photoelectric cells and additional cells'are placed in compartment6 in thetop of the cabinet. A seat 7 is provided forthe person to' be scanned. A "bank of cells 8 to 17 .is provided in the com- .partmentf5 at the left (as shown) and a simiis placedin compartcells, for example, cells 8 and 13. A box-like container 22 is mounted upon the vertical wall 23. of the cabinet and contains a sponge rubber partition 24 which serves as a partial support for the cells 8 and 13. The other ends 0f the cells are supported at the container ends by sponge rubber inserts 25, 26'. Sponge rubber elements27 are in the formjof segneath, in the rear and at the tops. Slots-28 are ments of. acircle and support the tubes underprovidedin the wall 23 to provide apartial view of the cells from the net. and to provide for the attachment of lead -wires 29. The otherterminals of the photooutside of the cabiof the; field but that it.

Such distribution of photoelectric and :provides These lamps are of'the filed April 6, 1927. Filters 31 for cell 14 are blue, for cells 8,9, 11,

for cells 13, 10 and 17 are green, and

12, 1 5 and 16 are red. A corresponding arrangement of filters occurs in I the compartment '5 at the right. The filters for cells 18 and 20 are greenand for cells 19 and21 are red. A metallic grating 32 covers the cell banks. This is connected to ground cells. Translucent glass plates 33 are providan electrostatic shield for the ed between; the subject and the various banks of cells and in part form the innermost walls of the cabinet.

Referring to Fig. 3 the cell banks, scanning discs, motor therefore,

shown in perspective.

, The cell bankat the right hand compartment 5 of Fig; 1 is at the left in Fig. 3 and comprises cells 8' to 17 p All of the cellshaving blue filtersare electrically connectedin parallel asshown and to a common amplifier 34. Similarly the cells having green filters are connected together and to amplifier 35' and the cells having red filters are connected together and to amplifier 36. These three amplifiers are connected respectively to amplifiers 37, 38 and 39 andthe latter amplifiers are respectively connected to the three transmission lines B, G and R. At the receiving station the currents received over the three channels are associated respectively with amplifiers 10, 4:1 and 42 which discharge lamps 13, 14 and 45.

control glow type disclosed in an lV. VVeinhart Serial 1N0.

application of H. I g

26, 1929. In front of the 373,818, filed June lamps are light filters 16, 17 and 48 respectively. Filter i6 transmits. blue light, filter 47 green 43 and Marc argon filled lamps'and lamp 15 is filled with neon. Any suitable known light sources for producing the primary colors may be substituted for those here shown. Transparent mirrors 19 and; 50 receive light from thalamps in the manner and light source are shown light, and filter 48 red light. Lamps shown to obtain a composite or mixed beam of light of the three primary colors which is transmitted through lenses 51v and 52 to a J of observation 53. Theiusual form of scanning disc 5A is driven by motor 55. A beamof light from are 56 illuminates the effective field of the scanning disc 54 and point causes a narrow beam of intense light to I traverse object 57 in adjacent horizontal lines. A receiving scanning disc 58 has its effective field within the beam of composite light at the receiver. The scanning discs 54" and 58 are maintained in exact synchronism by any suitable means such as the system disclosed in an application of H. M. Stoller and E. R.

igsaa lri Morton, Serial No. 181,314, filed "April 16, 1927. 3 The operation of the system should be apparent from theabove description. Reflected transmitter which is at that instant being illuminated. Since the observer at that instant observes only that elemental area of the receiving field of view which corresponds to the illuminated elemental area at' the transmitter the color of the elemental area at the receiver corresponds to that at the transmitter. This process is repeated as'the successive elemental areas are scanned so that the entire image is produced in natural color.

An initial adjustment of the receiving andplifiers is ordinarily made such that the composite beam of light produced by the three glow lamps appears white.

Preferably the direct current components of the photo-electric currents are transmitted to the receiver along with the alternating current components. If, however, the direct current components are suppressed at the transmitter the receiving operator may adjust the grid biases of the receiving amplifiers as the general tone of the transmitting field changes,'instructions for this purpose being transmitted from the transmitting operator to the receiving operator over a telephone line not shown. An application of H. E. Ives and F. Gray, Serial No. 181,511, filed April 6, 1 927, discloses adjustment of the receiving amplifiers for the reinsertion of the correct amount of direct current com-' ponent.

While it is not essential to the operation of this system, improved results are obtained by the use of mirrors 59-whic'h direct light to the photoelectric cells which would otherwise not reach them. Color patches are sometimes apparent in the image due to the large size of the light filters 31 and the proximity to the subject unless the translucent screen 33 is placed between the object and the light filters. This screen may be made up of two thicknesses of glass of the kind in' which one surface is plain and the other contains parallel ribs. The ribs of one plate are preferably at right angles to those of the other. Ihis forms a very efficient translucent screen.

While it is stated above that the filters '31 transmit primary colors, a more correct statement is that each of the filters transmits a band in which the primary color is present. An amount of primary color is transmitted so that by proper adjustment at the receiver I andproper selection of thelight beams at the receiver, a combination of light may be there obtained which will whenmixed give the appearance of white.

l/Vhiile the cell banks'in the embodiment of the invention above described are in planes -Wl1i'0'll converge toward the front of the cabinet, it is to be understood that the invention is not limited in this-respect sinceobviously it would-be desirable in certain cases to have the light sensitive material distributed in pil'anessubstantially parallel to the main horizontal axis of the field or to employ. some other distribution of the light sensitive material in conformity with the general principle laid down above.

What is claimed is 1'. scanning cabinet for television sys tems comprising a 'wall provided with an cpening through which a beam of light may. pass for traversing theJObject andbanks of large photoelectric acellswithin said cabinet and on different sides of said opening and in different planes respectively. i

p 2; A scanning cabinet for television systems comprising a wall havingan opening through which passes a beam of light for traversing the object and a bank of largephotO electric cellsat either side of said opening and in planes intersecting said. wall at a considerable distance from said opening.

3. A scanning cabinet for television systems comprising a wall having an opening for passing a beam of light which traverses the object to be scanned, banks of large photoe-lec'tric cells on different sides of said opening and in different planes, said photoelectric cells receiving reflected light from the object, and mirrors within said cabinetfor reflecting'light from said object to said cells.

43A scanning cabinet'for television systems comprising a wallhaving an opening therein for a beam of light for traversingthe object, and'three banks of large photoelectric cells for receiving reflected light from the object,"one ofsaid banks being at one side of the object within the cabinet, another bank on the opposite sideof the object, and the third bank above the object, said banks being in planes which intersect said wall and which aregenerally convergent toward said wall.

5. In a television system, means forscann-ing an object comprising means for traversing a beam of light over the object and light sensitive surfaces for receiving light reflected from sald ob ect,sa1d surfaces belng arranged in intersecting planes.

6; In a television system, means forscan ning an object comprising means for traversing a beam of light over the object, and means for receiving light reflected from the object comprising light sensitive elements of large effective area arranged in different planes on two sides of the object respectively.

'7. In a television system, means for scanning versing a an. object comprising means :for trabeam of light over the object, light "sensitive means for receiving light from within a Wide solid angle reflectedfrom'one side of said object and similar light sensitivemeans for receiving light from Within a Wide solid angle reflected from another side of'said .object, said lightsensitive means being Widely spaced apart and in different planes.

A-television' system comprising a light source, means including said light source for producing a moving beam of light forilluminating three dimensional objects in a field of view, lightsensitive material for receivingre-' fiected light from said field, portions of said ,inaterial lying on one side of said field and so positioned as to be intersected by 'aplane perpendicular to the central position ofsaid beam and passing through 'or behind the scannedelem'ental' areas most remote from said light source andother portions'ofsaid material being so positioned as to be intersected by a second plane parallel to the first and nearer to the light source than any scannedelemental areas, and means for setting up image currents corresponding to the amount'of'light received by said light sensiive material. I I

9.v The 'method of operating a television system comprising a light source, means including said light source'for producing a moving beam oflight for illuminating three dimensional objects in a field ofyview, light sensitive material portions of which are.

Widely separated in the general direction of said beam for receiving reflected light from said field, and means for setting up image currents corresponding to the amount of light received by said light sensitive material, Whichmethod comprises positioning the obj ect or objects in said field so that the scanned elemental areas most remote from said light source lie near to or in front of aplane perpendicular to the central .posltion of sald beam and passing through the portion of the light sensitive material most remote from said light source;

10. The method of. operating. a television system comprising a light source, means including said light source for producing a moving beam of light for illuminating three dimensional objects in a field of view, light sensitive material for receiving reflected light 'from said field, a part of said light sensitive material being distributed laterally of said field and having portions; Widely separated in the general direction of the scanning beam,

and means for setting up image currents corresponding to the amount of light received by said light 1 sensitive material, which method comprises positionng the objector objects in, said field so that the scanned elemental areas most remote from said light source lie near to or in front of a plane per- .pendicular to the central. position of said said :light source.

. system having a lightsource, means includ- -1ng said light source for producing a moving [beam andpa'ssing through the portion-of the light sensitive material most remote from 11. The method of operatinga television beam, of light for illuminating three; dimensional objects in a field ofyiew, light sensi-' tioned near thefront of andabovesaid field and having a portion widelyseparated 1n the general directionof the scanning beamfrom I a portion of said first part, and means for setting up mage currents correspondlng to the amount of light receivedby said light sensitive material, which method comprises positioning the objector objects to be scanned in said field near to or in front of aplane perpendicutive material for receiving. reflected light 'from said field, part of said light sensitive material being positioned laterally of said field at one side,- another part being'posilar to the central position of said beam. and

passing througha portion of said first part of said light sensitive material.

12. The method of operating-a television systemhavlng a light source, means includmg sa1dl1ght source ,forproducing a moving beam oflight for illuminating three dimensionalobjects in a field'of vie\;v, light sensitive material for receiving. reflected light from said field, part of said. light sensitive .material being positioned laterally of said field at one side,- another part being positioned near the front of and above said field and having a portion Widely separated. in the general direction of the scanning beam from a portion of said first part, and a third part of said material being positioned on the opposite side of said fieldfrom said first part, and means for setting up image currents corresponding to the amount of light received'by said light sensitive material, which method comprises positioning the'object or objects to be scanned in said field near to or in front of a plane perpendicularto the central position field on at least one side, and means forset- 1 ting up image currents corresponding to the amount of light received by said light sensi tive material. i.

14. A television system comprising means for defining, a three dimensional field of view of said beam and passing through a portion ,of said first part ofsaid light sensitive main which a three dimensional object or objects to be scanned are to be positioned, means including a light source for projecting into said field from the front thereof a moving scanning beam, light sensitive material for receiving light reflected from said field a portion of which is distributed laterally on at least one side thereof and to a point near the rear thereof and another portion of which is distributed in front of said field, and means for setting up image currents corresponding to the amount of light received by said light sensitive material.

15. A television system comprising means for defining a three dimensional field of view in which a three dimensional object or objects to be scanned are to be positioned, means including a light source for projecting into said'fie-ld from the front thereof a movingscanning beam, light sensitivematerial for receiving light reflected from said field having a portion distributed laterally on at least one side thereof and extending at least to a point near the rear thereof, light reflecting means for increasing the amount of light received by said light sensitive material from said field, and means for setting up image currents corresponding to the amount of light received by said light sensitive material. v v

16. Television apparatus for scanning three dimensional objects comprising alight source, means including said light source for producing a moving beam of light for successively'and repeatedly illuminating elemental areas of the object or objects in a three dimensional field ofview, and means for setting up image currents including means positioned laterally of the field for receiving light reflected laterally from illuminated elemental areas within the field.

17. Television apparatus for 1 scanning three dimensional objects comprising a light source, means including said light source for producing a moving beam of lightfor successively and repeatedly illuminating elemental areas of the object or objects in a three dimensional field of View, and means for setting up image currents including refiected-light-receiving means portions of which are positioned forwardly of the field and other portions of which are positioned laterally of the field whereby the effect of similar illumination of differently oriented illuminated elemental areas of three dimensional objects within the field may, if desired, be obtained.

18. Television apparatus for scanning three dimensional objects comprising a light source, means including said light source for producing a moving beam of light for successively and repeatedly illuminating elemental areas of the objector objects in a three dimensional field of view, and means for setting up image currents including light sensitive material positioned laterally of the field for receiving light reflected laterally from illuminated elemental areas within the 19. Television apparatus for scanning three dimensional objects comprising a light source, means including said light source for producing a moving beam oflight for successively and repeatedly illuminating elemental areas of theobject or objects in a three dimensional field of view, and means for setting up image currents including light cessively and repeatedly illuminating elemental areas of the object or objects in a three dimensional field of view, and means for setting up image currents including refiected light-receiving means portions of which are positioned forwardly of the field and other portions of which are respectivelypositioned laterally of the field on at least two sides thereof.

' "In witness whereof, we hereunto subscribe our names this 26th day of June, 1929.

c I HERBERT E. IVES.

, FRANK GRAY. 

